POU Filters Reduce ArF Lithography Defects

摘要

Bottom antireflective coatings (BARCs) have been widely used in the lithography process for decades. BARCs play important roles in controlling reflections and therefore improving swing ratios, CD variations, reflective notching and standing waves.rnThe implementation of BARC processes in 193 nm dry and immersion lithography has been accompanied by defect reduction challenges on fine patterns.rnPoint-of-use (POU) filters are well known among the most critical components on a track tool to ensure low wafer defects by providing particle-free coatingsrnon wafers. The filters must have very good particle retention to remove defect-causing particulate and gels, while not altering the chemical formulation of photochemical materials.